1. Technical Field
The present invention relates to an apparatus for testing electronic components including semiconductor dies or semiconductor packages, and more particularly to a test carrier for testing the same.
2. Description of the Related Art
In general, semiconductor packages or semiconductor dies are tested for defects and/or electrical characteristics prior to shipment to customers. This testing is typically done on a tester that is capable of evaluating many semiconductor packages simultaneously. Therefore, the tester utilizes a test carrier board that holds many semiconductor packages simultaneously. The test carrier board is used to position the semiconductor packages or semiconductor devices, also referred to as devices under test (DUTs), over a test head which individually engages with external contact terminals of the semiconductor packages through a plurality of test probes. The tester head generates test signals to test the electrical characteristics of the semiconductor packages. The test signals are transmitted to the semiconductor packages via test probes.
The test carrier board typically includes a plurality of test carriers that each receive an individual semiconductor package. As semiconductor packages have been shrinking in response to consumer demand, the area available on the semiconductor package to engage with the test carrier is correspondingly decreased. Further, if the test carrier is not able to reliably engage with a semiconductor package and hold the package in a fixed position, the test head may not make good connections with all of the external connection terminals. This may cause the semiconductor device in the package to be identified as a reject, when in fact the semiconductor device is not defective. Thus, conventional test carriers can result in a reduction in yield that is not due to actual defects. Consequently, a need remains for a test carrier that is capable of reliably engaging semiconductor packages with small dimensions as explained below.
FIG. 1 is a plan view and a side view of a conventional BGA type semiconductor package. As shown in FIG. 1, a conventional BGA type package 50 includes a plurality of external connection terminals 45 disposed in an array below an encapsulated semiconductor device 40. In order to meet demand for smaller and/or thinner semiconductor packages, the overall dimensions of the encapsulated semiconductor device are continually decreasing. Therefore, a distance (dimension A in FIG. 1) between the edge of the encapsulation (or the edge of the semiconductor package) and the edge of the external connection terminal array (or an outermost portion of the external connection terminal array) is correspondingly decreasing.
FIG. 2 is a cross-sectional view of an exemplary conventional test carrier and a test head. As shown in FIG. 2, a conventional test carrier 10 includes only a single set of latches 20 that engage a DUT on a single surface. Thus, the opposite surface of the semiconductor package must engage with a shelf 12 on the test carrier 10.
FIG. 3 is an expanded view of a shelf in a conventional test carrier. As shown in FIG. 3, a conventional test carrier 10 includes a shelf 12 that engages with a lower surface of a semiconductor package. The shelf 12 must engage with a sufficient portion of the lower surface of the semiconductor package such that the semiconductor package can be adequately supported by the shelf. Also, the shelf 12 should not contact the external connection terminals 45 because the shelf 12 may damage the external connection terminals 45, or the shelf 12 may prevent proper contact between the external connection terminals 45 and a test head during the testing operation. If the shelf 12 damages the external connection terminals 45, the semiconductor package will be defective and unusable. If the shelf 12 prevents contact between the test head and the external connection terminals 45, the semiconductor package may be wrongly classified as defective, when in fact the semiconductor package is not defective. Both of these situations result in a reduction in yield and a corresponding increase in manufacturing costs. Therefore, a minimum distance A is required between the edge of the external connection terminal array and the edge of the encapsulation of the semiconductor package to ensure that the shelf 12 of the conventional test carrier 10 provides adequate support for the semiconductor package and does not contact the external connection terminals 45. However, as the size of the semiconductor package continues to decrease, in order to meet consumer demand, securing the minimum distance A becomes difficult, if not impossible, to achieve. In some instances, the semiconductor package falls through the test carrier due to in sufficient support area (very small minimum distance A). Consequently, it becomes difficult to test the modern semiconductor packages with the conventional test carriers discussed above.
Therefore, a novel test carrier is needed that provides adequate support for a semiconductor package but does not require a minimum distance between the edge of the external connection terminal array and the edge of the encapsulation of the semiconductor package. The present invention addresses these and other disadvantages of the conventional art.